I found these bugs wandering around on my prickly pears -- you can see the lighter color of the leaf is where they've been and nibbled -- We have a lot of cactus, yucca, bamboo, succulents etc... but these guys are only on the prickly pears and spread through out the balcony.
These are nymphs of an Opuntia/cactus joint bug in the genus Chelinidea (either C. tabulata or C. vittigera; Hemiptera/Heteroptera: Coreidae). See http://tinyurl.com/cb9p7v and http://tinyurl.com/dzoefb for images. The nymphs reportedly can be quire variable in coloration.
